I think the second sentence of your argument is more compelling to me than the first.
Weidman said the same thing about clowning being a tactic after his win. Did Anderson clown sometimes, sure. Was is some key element of his strategy? IMO, no. He just smoked guys and occasionally got bored.
I think what he did against Weidman was a combination of a general complacency in his career plus ego kicking in when Weidman landed some shots on him. I don’t think he was hurt at all, but he still got hit and it bruised his ego. He emphasized resolving that temporary discomfort over accepting that he was in a tough fight and embracing the challenge.
In hindsight, it seems clear that Anderson was going to lose his title soon. Was it always going to be Weidman? I think Weidman would probably have been the favorite if we could run that fight 100 times in a simulation. He had the good wrestling that had caused Anderson problems against Chael, plus serviceable striking, and most importantly he was younger, more focused more physically robust, more aggressive, etc. Anderson was a far superior technical striker, so he’s gonna catch Weidman and stop him a fair amount of the time, but I don’t think it’s fair to call what happened a fluke. Both fights ended in flukey, or at least unusual ways, but the torch was likely to pass soon one way or the other and Weidman was as good a bet as anyone else.